Hey guys.

I'm thinking of changing the brake levers on my bike for a spare set i have which are a lot smoother, and I find seem to fit better in my hand/fingers, if that makes sense.

Only problem is, they seem to be missing a screw, as shown in pics.

Spare levers:





Current levers:





A few questions:

What does this screw do? If it adjusts something, what does it adjust?

Will it be ok to use the levers without this screw in place? If not, will I be able to use the screw which is in my current levers?

Also, is it fairly straight forward to do the switch?

Sorry about any silly questions, I'm still learning

Thanks,
Luke.